The invention relates to a pump for flowable media, particularly a cosmetic pump, provided with a base, which can be mounted tightly on the opening of a container and, when mounted, has an underside facing the container and a top side facing away from the container, a through-hole in the base, which extends from the underside of the base through to its top side, a tube sleeve extending upwards from the top side of the base around the through-hole, an outer guide sleeve extending upwards from the top side of the base, a top part guided on the guide sleeve that can be manually depressed against a compression spring, a compression chamber adjacent to the tube sleeve with an inlet valve and an outlet valve, an outlet channel provided downstream of the outlet valve of the compression chamber, a mounting element provided on the underside of the base for connecting the base to the container, a riser tube extending from the through-hole into the container for drawing in the flowable medium and a forced-ventilation element to the inside of the container that is active when the top part is depressed.
Pumps of the kind described are mass-produced components that are usually intended to discharge the contents of a single container and then have to be disposed of. They serve to transport various flowable media, particularly in the field of body and beauty care, where cleansing lotions, creams and the like are to be pumped to the outlet opening of the respective container, for example.
Pumps of this kind must be inexpensive to manufacture and easy to assemble, because their price should not significantly increase the total price of the product, comprising the container, the contents and the pump.
Various designs of pumps of this kind are known, such as from German patent 19 645 393.
The object of the invention is to further simplify the design of a pump of this kind.
According to the invention the object is solved in that both the inlet valve and the outlet valve of the compression chamber are designed as integrally moulded lip seals that only allow the medium to pass in the direction of transport, where the medium is drawn into the compression chamber by the upward travel of the top part induced by spring force and forced out of the compression chamber when the top part is depressed, the lip seal that serves as the inlet valve is preferably located on the outer periphery of the tube sleeve with its sealing lip in contact with the inner surface of the chamber sleeve, and in that the lip seal that serves as the outlet valve of the compression chamber can be located on the inner periphery of the chamber sleeve provided on the top part with its sealing lip in contact with the outer surface of the tube sleeve.
In this way, the compression chamber, which is enclosed by the two lip seals, is formed between the tube sleeve integrally moulded on the base and the chamber sleeve provided on the top part. As a result, no separate parts that can shift relative to one another are required to form the valve area, as is the case with the known pumps.
A pump of this kind consists of a maximum of three parts, namely the base, the depressible top part and a restoring spring.
If the restoring spring is integrally moulded on the top part, or possibly on the base, the pump according to the invention can be made of two parts, which need only be pressed together after being produced.
The tube sleeve of the base can be designed as an elongated cylinder that is closed at the top end.
In a design of this kind, the compression chamber is expediently located between the outer surface of the tube sleeve and the inner surface of a chamber sleeve located on the top part concentric to the tube sleeve.
The tube sleeve can expediently be provided below the lip seal with at least one aperture for the medium to be transported, which thus exits the tube sleeve below the lip seal.
A displacement chamber, into which the tube sleeve designed as a cylinder closed at the top projects, is expediently located above the outlet valve inside the chamber sleeve and/or the top part. Thus, when the top part is depressed, not only is the medium to be transported pumped through the outlet valve towards the outlet channel, but the displacement chamber also becomes successively smaller, thus intensifying the pump effect.
The downward movement of the top part can be limited by the top end of the tube sleeve hitting the top end of the displacement chamber, meaning that no additional stops need be integrally moulded.
Another circumferential sealing lip, which also contacts the inner surface of the chamber sleeve, can be provided below the aperture on the outer periphery of the tube sleeve, where the area between the two sealing lips provided on the tube sleeve forms an intermediate chamber. From this intermediate chamber, the medium to be transported can only be pumped towards the compression chamber, while the passage of the medium downwards into the other parts of the pump is prevented by the lower sealing lip.
Furthermore, the base can be provided with a sealing lip that contacts the outer periphery of the chamber sleeve, thus preventing air from entering the pump from the outside during the pumping cycle. In order to nonetheless ensure forced ventilation to the inside of the container after the pumping cycle, the outer periphery of the chamber sleeve can have at least one recess, which is in the region of the sealing lip when the top part is depressed and thus creates an air opening. At the same time, at least one air passage is expediently provided in the base between the tube sleeve and the sealing lip, through which the air can directly enter the container.
The top part is expediently provided with a corresponding guide sleeve that interacts with the guide sleeve of the base. The two guide sleeves not only serve as the outsides of the pump, but can also be provided with stops to limit the upward stroke of the top part.
The tube sleeve of the base and the chamber sleeve of the top part can be concentric relative to one another.